I often see TV shows that talk about loved ones becoming angels when they die, and I'm pretty sure that a lot of people believe that. Shows like "Highway to Heaven" help to perpetuate that false belief. It was about a man (played by Michael Landon) who died from lung cancer from all his smoking, and he becomes an angel and was sent to earth to help people. He had powers to do all kinds of things but wasn't allowed to use them for personal gain.
People often believe that their loved ones are in heaven watching over them. I'm not sure that does any harm, but it is wrong if they're trusting in their dead loved ones rather than in Christ. Of course, in those TV shows that even mention angels, the name of Christ is never mentioned. A lot of people who don't mind you saying "God loves you", but they don't want to hear that "Jesus died for your sins." Nor do they want to hear that Jesus is the ONLY way to heaven.